Contributor: CHRIS PRIEDE
Function LastDrive: Char; Assembler;
Asm
mov ah, 19h
int 21h
push ax { save default drive }
mov ah, 0Eh
mov dl, 19h
int 21h
mov cl, al
dec cx
@@CheckDrive:
mov ah, 0Eh { check if drive valid }
mov dl, cl
int 21h
mov ah, 19h
int 21h
cmp cl, al
je @@Valid
dec cl { check next lovest drive number }
jmp @@CheckDrive
@@Valid:
pop ax
mov dl, al
mov ah, 0Eh
int 21h { restore default drive }
mov al, cl
add al, 'A'
end;
(*
LastDrive will return letter of the last valid drive. To check
if the drive letter entered is valid:
if Upcase(DriveLetter) <= LastDrive
then {valid drive}
else {bad drive};
*)